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Importin α/β mediates nuclear import of individual SUMO E1 subunits and of the holo-enzyme

SUMOylation, reversible attachment of small ubiquitin-related modifier (SUMO), serves to regulate hundreds of proteins. Consistent with predominantly nuclear targets, enzymes required for attachment and removal of SUMO are highly enriched in this compartment. This is true also for the first enzyme o...

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Autores principales: Moutty, Marie Christine, Sakin, Volkan, Melchior, Frauke
Formato: Texto
Lenguaje:English
Publicado: The American Society for Cell Biology 2011
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3046061/
https://www.ncbi.nlm.nih.gov/pubmed/21209321
http://dx.doi.org/10.1091/mbc.E10-05-0461
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author Moutty, Marie Christine
Sakin, Volkan
Melchior, Frauke
author_facet Moutty, Marie Christine
Sakin, Volkan
Melchior, Frauke
author_sort Moutty, Marie Christine
collection PubMed
description SUMOylation, reversible attachment of small ubiquitin-related modifier (SUMO), serves to regulate hundreds of proteins. Consistent with predominantly nuclear targets, enzymes required for attachment and removal of SUMO are highly enriched in this compartment. This is true also for the first enzyme of the SUMOylation cascade, the SUMO E1 enzyme heterodimer, Aos1/Uba2 (SAE1/SAE2). This essential enzyme serves to activate SUMO and to transfer it to the E2-conjugating enzyme Ubc9. Although the last 40 amino acids in yeast Uba2 have been implicated in its nuclear localization, little was known about the import pathways of Aos1, Uba2, and/or of the assembled E1 heterodimer. Here we show that the mammalian E1 subunits can be imported separately, identify nuclear localization signals (NLSs) in Aos1 and in Uba2, and demonstrate that their import is mediated by importin α/β in vitro and in intact cells. Once assembled into a stable heterodimer, the E1 enzyme can still be efficiently imported by importin α/β, due to the Uba2 NLS that is still accessible. These pathways may serve distinct purposes: import of nascent subunits prior to assembly and reimport of stable E1 enzyme complex after mitosis.
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spelling pubmed-30460612011-05-16 Importin α/β mediates nuclear import of individual SUMO E1 subunits and of the holo-enzyme Moutty, Marie Christine Sakin, Volkan Melchior, Frauke Mol Biol Cell Articles SUMOylation, reversible attachment of small ubiquitin-related modifier (SUMO), serves to regulate hundreds of proteins. Consistent with predominantly nuclear targets, enzymes required for attachment and removal of SUMO are highly enriched in this compartment. This is true also for the first enzyme of the SUMOylation cascade, the SUMO E1 enzyme heterodimer, Aos1/Uba2 (SAE1/SAE2). This essential enzyme serves to activate SUMO and to transfer it to the E2-conjugating enzyme Ubc9. Although the last 40 amino acids in yeast Uba2 have been implicated in its nuclear localization, little was known about the import pathways of Aos1, Uba2, and/or of the assembled E1 heterodimer. Here we show that the mammalian E1 subunits can be imported separately, identify nuclear localization signals (NLSs) in Aos1 and in Uba2, and demonstrate that their import is mediated by importin α/β in vitro and in intact cells. Once assembled into a stable heterodimer, the E1 enzyme can still be efficiently imported by importin α/β, due to the Uba2 NLS that is still accessible. These pathways may serve distinct purposes: import of nascent subunits prior to assembly and reimport of stable E1 enzyme complex after mitosis. The American Society for Cell Biology 2011-03-01 /pmc/articles/PMC3046061/ /pubmed/21209321 http://dx.doi.org/10.1091/mbc.E10-05-0461 Text en © 2011 Moutty et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0). “ASCB®,“ “The American Society for Cell Biology®,” and “Molecular Biology of the Cell®” are registered trademarks of The American Society of Cell Biology.
spellingShingle Articles
Moutty, Marie Christine
Sakin, Volkan
Melchior, Frauke
Importin α/β mediates nuclear import of individual SUMO E1 subunits and of the holo-enzyme
title Importin α/β mediates nuclear import of individual SUMO E1 subunits and of the holo-enzyme
title_full Importin α/β mediates nuclear import of individual SUMO E1 subunits and of the holo-enzyme
title_fullStr Importin α/β mediates nuclear import of individual SUMO E1 subunits and of the holo-enzyme
title_full_unstemmed Importin α/β mediates nuclear import of individual SUMO E1 subunits and of the holo-enzyme
title_short Importin α/β mediates nuclear import of individual SUMO E1 subunits and of the holo-enzyme
title_sort importin α/β mediates nuclear import of individual sumo e1 subunits and of the holo-enzyme
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3046061/
https://www.ncbi.nlm.nih.gov/pubmed/21209321
http://dx.doi.org/10.1091/mbc.E10-05-0461
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